MEXICO CITY — Mexican soccer fans loudly booed the United States national anthem when it was played moments before the start of Sunday night's World Cup qualifier between the two countries.

Thousands of supporters at the Estadio Azteca in Mexico City whistled and jeered as the Star-Spangled Banner played over the stadium sound system, with most of the crowd refusing to stand.

The match was a critical one for the USA, which had endured a shaky start to the final round of World Cup qualifying in the CONCACAF region.

Contrary to before the last time the teams met, in Columbus, Ohio, in November, the squads lined up separately for ceremonial photos. In Columbus, they bucked tradition by posing for a pregame "unity" photo.